Experimental and Theoretical Analysis of Strain Engineered Aluminium Nitride on Silicon for High Quality Aluminium(x)Indium(y)Gallium(1-x-y)Nitride Epitaxy

III-Nitrides on Si are of great technological importance due to the availability of large area, epi ready Si substrates and the ability to heterointegrate with mature silicon micro and nanoelectronics. The major roadblock with realizing this is the large difference in thermal expansion coefficients and lattice constants between the two material systems. A novel technique developed in our research lab shows the potential of simultaneous and substantial reduction in dislocation and crack density in GaN on Si (111). Research undertaken in the current doctoral dissertation, validates the superior GaN quality on Si obtained using our technique and determines the factors responsible for its successful implementation.;Detailed study of the stress evolution and dislocation reduction mechanism within overgrown GaN on as-grown and engineered AlN/Si substrates is carried out. Based on the conclusions obtained in this study, a pulsed metal-organic chemical vapor deposition (MOCVD) technique for the growth of AlN on Si (111) is developed to achieve a smoother AlN buffer with larger islands. A 14x reduction in surface pit density for overgrown GaN is attained on these AlN/Si substrates after substrate engineering. Deep green emission at 560 nm from InGaN/GaN MQWs with 10x increase in photoluminescence (PL) intensity is obtained on these templates.;Molecular dynamics (MD) is used with an ultimate goal to theoretically understand the stress dilution mechanism and assist in improving the technique experimentally. Plausible models to accurately simulate wurtzite AlN (w-AlN) and AlN on Si (111) are developed. Motion of Si islands on Si (111) bulk substrate is examined to assess the required simulation conditions, their compliance with experimental set-up, and the limitations. Homoepitaxial growth of w-AlN is carried out to simulate epitaxial deposition as a starting point for heteroepitaxy of AlN on Si (111) and also to eventually build the entire complex film stack that closely resembles the experimental substrate engineering process.;Finally, crack-free III-N device structures, greater than 3.5 microm in thickness, across an entire 2" Si wafer are developed. The impact of combining our stress dilution technique with conventional strain management techniques on the performance of high electron mobility transistor (HEMT) devices is assessed.